Redoing the calculations for North America

The average American uses 250 kWh per day. Can we hit that target with
renewables? What if we imagine imposing shocking efficiency measures
(such as efficient cars and high-speed electric trains) such that Americans
were reduced to the misery of living on the mere 125 kWh/d of an average
European or Japanese citizen?


A study by Elliott et al. (1991) assessed the wind energy potential of the
USA. The windiest spots are in North Dakota, Wyoming, and Montana.
They reckoned that, over the whole country, 435 000 km2 of windy land
could be exploited without raising too many hackles, and that the electricity
generated would be 4600 TWh per year, which is 42 kWh per day
per person
if shared between 300 million people. Their calculations ass-
umed an average power density of 1.2 W/m2, incidentally – smaller than
the 2 W/m2 we assumed in Chapter 4. The area of these wind farms,
435 000 km2, is roughly the same as the area of California. The amount
of wind hardware required (assuming a load factor of 20%) would be a
capacity of about 2600 GW, which would be a 200-fold increase in wind
hardware in the USA.

Offshore wind

If we assume that shallow offshore waters with an area equal to the sum
of Delaware and Connecticut (20 000 km2, a substantial chunk of all shal-
low waters on the east coast of the USA) are filled with offshore wind
farms having a power density of 3 W/m2, we obtain an average power of
60 GW. That’s 4.8 kWh/d per person if shared between 300 million people.
The wind hardware required would be 15 times the total wind hardware
currently in the USA.


I mentioned the MIT geothermal energy study (Massachusetts Institute of
Technology, 2006) in Chapter 16. The authors are upbeat about the pot-
ential of geothermal energy in North America, especially in the western
states where there is more hotter rock. “With a reasonable investment
in R&D, enhanced geothermal systems could provide 100 GW(e) or more
of cost-competitive generating capacity in the next 50 years. Further, en-
hanced geothermal systems provide a secure source of power for the long
term.” Let’s assume they are right. 100 GW of electricity is 8 kWh/d per
when shared between 300 million.